The present invention relates to a water jet web edge trimmer having a trim chute integral and moveable therewith for cutting a leader strip and new edge into a travelling web and disposing of the strip into the trim chute.
In the papermaking industry, knives or water jets are commonly employed to cut through the traveling web or sheet. The knives and water jets are used in edge trimming, slicing, cross-cutting, and tail cutting applications within the papermaking machine. However, when the knives or water jet cutters are used in an edge trimming application, trim chutes or bins are located downstream from the cutter of the strip of web material trimmed from the main portion of the web.
Typically, a trim chute relies on some form of negative pressure to draw the trim strip into the chute. The higher the machine speed and further the trim chute is located from the edge trimming or cutting point, the more the risk of having the trim either not follow a normal path into the trim chute or the more the requirement for corrective forces to draw or guide the strip into the trim chute.
Water jet cutters currently in use typically cut through a web passing over a web support plate or table. The location of the trim chute is downstream and separated from the water jet cutting device. This results in the trim chute having to be located under the path of the travelling web downstream of the web including that portion of the web that remains on the edge of the web as the new edge of the web is cut into the web. This is also true for the water jet cutting head disclosed in U.S. Pat. No. 6,021,699 issued Feb. 8, 2000 to Roman Caspar. In this patent a water jet cutting head is disclosed that is capable of supporting the web while at the same time cutting a leader and new edge in the travelling web; however, there is no disclosure in this patent with respect to the disposal of the trimmed strip from the web and this patent does not contemplate the disposal of the trimmed strip.
The present invention relates to the use of a moveable integral water jet cutting and trim chute unit that is adapted for relative movement inwardly of the outside edge of the web. The trim chute has an opening exposed to the new edge of the cut web that does not exert undo suction or guide pressures on the remaining web portion at all times during the cutting operation. This is accomplished by having a support plate with a water jet cutting aperture located therein and from which the trim chute is integrally supported extending out of and away from the plane of the web. In particular, the cutting aperture in the support plate is substantially aligned, and preferably located slightly inboard of, an inside or first edge defining the trim chute opening. As a result, the strip trimmed from the edge of the web is outboard of the cutting aperture and the remainder of the web is located, for the most part, inboard of this cutting aperture. Since the aligned edge of the trim chute is located either in line or slightly inboard of the cutting aperture, a restricted amount of negative pressure is applied from the opening of the trim chute to an edge of the remaining web portion. Thus a majority of this negative pressure acts to draw the strip into the trim chute. By having the support plate and the trim chute integrally connected, both the water jet cutter and the trim chute move in unison into the edge of the web maintaining the cutting aperture and the aligned first edge of the trim chute in a fixed position to each other. Further the distance the trim strip travels to the trim chute is relatively short.
In accordance with the preferred aspect of the present invention, the support plate further includes a plurality of suction apertures. The suction apertures are positioned substantially on an inboard side of a cutting aperture defined relative to the web to support the web after the trim strip has been cut and to permit the trim strip to be directed into the trim chute. The water jet nozzle is positioned on the side of the support plate opposite to the web (behind the support plate) in alignment with the cutting aperture to direct a water jet through the cutting aperture. The jet passes through the support plate and cuts through the web. Suction is applied to the support plate at the section apertures to draw the web portion on the inboard side of the cutting aperture into engagement with the support plate while permitting the remainder of the trimmed strip to pass into the trim chute.
The trim chute is integrally attached to the support plate preferably on the same side of the web plate as the support plate. The trim chute has a lead in curved surface immediately downstream of the cutting aperture that extends from the support plate and into the trim chute opening so as to provide a continuous path over which the strip passes. In an alternative embodiment, the trim chute extends out of the plane of the web on the opposite side of the web as the support plate. In this alternative embodiment, a continuous path of travel for the trimmed strip is provided between the support plate and the trim chute opening by the trim chute and support plate having overlapping flanges on opposite sides of the plane of the web which are interconnected by an outside edge flange member located outboard of the web and transversing the plane of the web. The overlapping flanges on opposite sides of the plane of the web effect the transfer from one flange associated with the support plate to the flange associated with the trim chute.
Since the trim chute is adapted to move relative to the web in unison with the support plate of the water jet cutter, a negative pressure is applied to the trim chute by a laterally moveable connection between two trim chute funnels whereby one funnel moves relative to the other stationary funnel and the moving funnel has an opening larger than the stationary funnel, or visa versa. Alternatively, a flexible hose maybe connected to the movable trim chute.
In applications where the web comprises a paper of a lighter basis weight, such as, for example, tissue or magazine paper, an additional second support plate is utilized. This second support plate is spaced from the first support plate on the opposite side of the web from the first support plate so as to sandwich the web between the two support plates as the cutting unit moves in from the edge of the web and continues to cut a trim strip from the web.
To effect simultaneous movement of the first and second support plates relative to the web, a movable carriage is provided for supporting first and second arm assemblies respectively on first and second opposing sides of the travelling web. The first arm assembly comprises the first support plate, the water jet nozzle, and the trim chute. The second arm assembly comprises the second support plate.
The second support plate has an opening aligned with the nozzle to permit effluent spray to pass. Preferably, the first and second support plates have leading curved edges to guide the web between the first and second support plates as the first and second arm assemblies are moved inwardly of the outside edge of the web.
It is also contemplated that the second arm assembly may further comprise a waste disposal post positioned and spaced from the second opposing side of the web aligned with the water jet nozzle to receive effluent spray from the nozzle after it cuts through the web.
In accordance with one aspect of the present invention, there is provided a movable integral water jet web cutting and trim chute unit adapted for relative movement inwardly of an outside edge of a web travelling in a first direction to cut a strip from the travelling web and to dispose of the strip. The moveable integral water jet web cutting and trim chute unit comprises a support plate adapted to extend relative to the plane of the travelling web to support the web immediately prior to and after the strip is cut from the edge of the travelling web as the unit moves relative to the web. The support plate has a cutting aperture. The unit comprises a water jet nozzle positioned behind the support plate in alignment with the cutting aperture for directing a water jet through the cutting aperture and away from the support plate to cut through the web and form the strip. The unit has a trim chute extending out of and away from the plane of the travelling web from the support plate. The trim chute has an opening in the support plate downstream of the cutting aperture. The trim chute opening is bounded by a first side edge extending in the first direction of web travel substantially in alignment with the cutting aperture to limit that portion of the web passing over the trim chute opening. The unit has negative pressure means associated with the trim chute for drawing the strip into and through the trim chute.
In accordance with another aspect of the present invention there is provided a moveable integral water jet web cutting and trim chute unit adapted for relative movement inwardly of an outside edge of a web travelling in a first direction to cut a strip from the travelling web and to dispose of the strip. The moveable web cutting and trim chute unit comprises a support plate adapted to extend relative to the travelling web to support the web immediately prior to and after the strip is cut from the outside edge of the travelling web as the web cutting and trim chute unit moves inwardly relative to the web. The support plate has a cutting aperture and a plurality of suction apertures. The suction apertures are positioned substantially on an inboard side of the cutting aperture defined relative to the web to support the web after the strip has been cut and to permit the strip to be directed into the trim chute. The unit has first negative pressure means associated with the suction apertures of the support plate for drawing the travelling web into engagement with the support plate adjacent the cutting aperture as the web passes over the support plate. The unit has a water jet nozzle positioned behind the support plate in alignment with the cutting aperture for directing a water jet through the cutting aperture and away from the support plate to cut through the web to form a new edge in the web and to form the strip. The unit has a trim chute extending from the support plate out of and away from the plane of the travelling web and located on the same side of the web as the support plate. The trim chute has an opening in the support plate downstream of the cutting aperture into which the strip passes. The unit has second negative pressure means associated with the trim chute for drawing the strip into the trim chute opening.
In accordance with still yet another aspect of the invention there is provided a moveable integral water jet web cutting and trim chute unit having an alternative embodiment for the trim chute wherein the trim chute extends out of and away from the plane of the travelling web and is located on the opposite side of the web as the support plate. The support plate has an outside edge flange member located outboard of the web and traversing the plane of the web to support the trim chute relative to the support plate. The trim chute and the support plate have overlapping flanges on opposite sides of the plane of the web to transfer the strip from the support plate flange to the trim chute flange. The trim chute has an opening downstream of the cutting aperture into which the strip passes.
In accordance with still yet another aspect of the present invention there is provided a moveable integral water jet web cutting and trim chute assembly adapted for relative movement inwardly of an outside edge of a web travelling in a first direction to cut a strip from the travelling web and to remove the strip. The moveable integral water jet web cutting and trim chute assembly comprises a movable carriage supporting first and second arm assemblies respectively on first and second opposing sides of the travelling web to move the first and second arm assemblies inwardly of the outside edge of the web. The first arm assembly comprises a first support plate, a water jet nozzle, and a trim chute. The first support plate is adapted to extend relative to the plane of the travelling web to support the web on its first side immediately prior to and after the strip is cut from the edge of the travelling web as the first and second arm assemblies move relative to the web. The first support plate has a cutting aperture. The water jet nozzle is positioned behind the first support plate aligned with the cutting aperture for directing a water jet through the cutting aperture and away from the support plate to cut through the web and form the strip. The trim chute extends out of and away from the plane of the travelling web from the support plate and has an opening in the support plate downstream of the cutting aperture. The second arm assembly comprises a second support plate adapted to extend relative to the plane of the travelling web and to be spaced from the first support plate for supporting the web on its second side immediately prior to the strip being cut from the edge of the travelling web as the first and second arm assemblies move relative to the web.